The highways ministry had rolled out IBMS in early 2016 after realising that there was no centralised list of bridges, and hence it depended on physical reports to undertake repair, maintenance or rehabilitation.NEW DELHI: Twenty-three bridges and tunnels on national highways (NHs) are over 100 years old, of which 17 require rehabilitation or major maintenance. As many as 123 other bridges in the country require immediate attention and 6,000 are structurally "distressed".

These are some of the findings of a analysis conducted by the Union road transport and highways ministry under its Indian Bridge Management System (IBMS) project, India's first-ever survey of the "health of bridges", launched last year.

The over-a-century-old structures include the Narmada bridge in Bharuch, Gujarat; two at Tikamgarh in Madhya Pradesh; and one each at Gulbarga in Karnataka, and Kolhapur and Pimri Chinchwad in Maharashtra. All of these need rehabilitation or major maintenance.

After the study, the ministry has found there are about 1.6 lakh structures, including culverts, minor and major bridges and flyovers on India's NH network. Each of the structures has now got a unique identity number under this initiative, and undergo periodic inspection.

Sources said highways minister Nitin Gadkari has asked the ministry, the National Highways Authority of India (NHAI) and the state public works departments, which manage NH stretches, to undertake immediate repair or rehabilitation work on structures that require immediate attention

. "He has also instructed that we should go for rehabilitation of the bridges if the cost of repair or strengthening is more than 30% of the cost of the bridge," a ministry official said.

Gadkari has also directed the entity dealing with the IBMS to install sensors on bridges on stretches that are largely used for movement of over-dimensional vehicles to carry heavy equipment such as electricity turbine, so that the "health" of these structures can be assessed in real time.

The highways ministry had rolled out IBMS in early 2016 after realising that there was no centralised list of bridges, and hence it depended on physical reports to undertake repair, maintenance or rehabilitation.

"The need to have this web-based system was felt so that we can take the decision for repair, rehabilitation or dismantling of the structures in advance. The collapse of a bridge or complete closure disrupts the traffic flow on a highway stretch, and these have a ripple effect on other stretches as well," said a ministry official.